Production method and apparatus



1965 c. E. WAKEFIELD, JR 3,282,336

PRODUCTION METHOD AND APPARATUS Filed Sept. 25, 1962 2 Sheets-Sheet l I flia A6.

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Nov. 1, 1966 c. E. WAKEFIELD, JR 3,282,336

PRODUCTION METHOD AND APPARATUS Filed Sept 25, 1962 g Sheets-Sheet z C w M A 5 K as war m/vz Q] o 54 1 E 30 I INVENTOR. 1 0/4245)" 5 WAKE/7620, 1e.

drrae/v a United States Patent 3,282,336 PRODUCTION METHOD AND APPARATUS Charles E. Wakefield, Jr., Bakersfield, Calif., assignor to Richfield 0i] Corporation, Los Angeles, Calif., a corporation of Delaware Filed Sept. 25, 1962, Ser. No. 225,983 8 Claims. (Cl. 166-5) The present invention relates to a device for producing oil and gas from a subterranean formation and more particularly relates to a modification of a production system for recovering oil and gas with a fluid operated pumping system conducted through a production head installed in a formation underlying a body of water.

In my copending application, Serial No. 100,411 filed April 3, 1961, an apparatus was disclosed for producing oil and gas wells in a formation underlying a body of water. This apparatus involved the use of a production mandrel with side outlets for the tubing, casing, etc. and was plugged off with a head plug at the upper end of the production head. When wells produced with the production head of the above device diminish in pressure and require the use of a pump for recovering additional oil and gas, access must be had to the well tubing.

It has been found that downhole fluid operated pumping systems are particularly useful with the production apparatus described in the aforementioned application. Conventional displacement type fluid-operated pumps, such as is disclosed in US. Patent No. 2,311,157, comprise a motor cylinder having a motor piston therein, a pump cylinder having a pump piston therein and connected by a piston rod with a motor piston, and master valve mechanism for alternately directing high-pressure operating oil to opposite ends of the motor cylinder to reciprocate the piston assembly to pump well fluid from the pump cylinder. A conventional fluid operated pumping system for an oil well involves at least two tubings set in the well, either concentrically or side by side. The pump set in the power section of the tubing is actuated by a fluid operated motor which is actuated by an operating fluid, preferably a power oil, under pressure, pumped down through one of the tubings from the surface. The other tubing is used for the discharge of well and/ or operating fluid. Such systems may be of the open or closed type, the distinction being that in the open type the operating fluid under pressure, which is supplied to the downhole pump, is discharged to the surface with the produced well fluid through a common tubing, rather than through a separate tubing string. In such systems, the fluid operated pump may be either the free or set type. The free type is movable through one of the tubings between the surface and its operating position adjacent the lower end of such tubing. Such a free pump system is disclosed in U.S. Patent No. 2,338,903. A sysstem for employing a free pump, which is preferably for offshore operation, advantageously requires access to the well tubing through the production head so that the pump may be recovered therethrough.

It is therefore an object on the present invention to provide an apparatus and a method whereby fluid communication may be established between a well head mounted on a formation underlying a body of water and a structure at or near the surface of the body of water.

It is a further object of my present invention to provide a modified fluid-operated pumping system useful in connection with a production head installed on a formation underlying a body of water.

It is also an object of the present invention to provide a modified production head which can be readily converted for fluid-operated pumping means.

Other objects and a more complete understanding of the present invention may be had by reference to the following specification taken in conjunction with the appended claims and the accompanying drawings where- FIGS. 1a and 1b show the production head modified in accordance with the present invention, for access to the production tubing through the well head for fluidoperated pumping operations.

FIG. 10 shows partially in section, the position of the downhole pump in the well tubing.

FIG. 2 shows partially in schematic, a fluid-operated pumping system in accordance with the persent invention.

Briefly described, my invention relates to a fluid-opera-ted pumping system, shown schematically in FIG. 2, which is adapted for use with a production head 18 whereby the tubing and casing outlets 31 and 32 are utilized to transmit power oil and return production fluid from an underwater oil and gas well, and the production head is modified to permit recovery of the fluid-operated pump without pulling the tubing from the well.

Referring more specifically to the drawings, FIGS. 1a and 1b show the production mandrel 10 more fully described in my aforementioned copending application, with a modified head plug 12 set in the mandrel. A valve housing 14 is attached to the top of the head plug 12 and houses a valve for closing off the top of the production head from longitudinal flow. The production head was previously closed off with a mandrel plug inside the tubing hanger mandrel, with a solid head plug with sealing rings serving as a secondary seal. The tubing valve 15 is preferably of the full opening plug, ball or gate type and may conveniently be remotely controlled from the drilling barge (not shown). Value 15 is normally closed as a top seal for the tubing hanger mandrel 13, but may be opened to circulate the downhole fluidoperated pump 30 out of the hole, as will be mentioned below.

A closure member such as bull plug 18 is attached to the upper end of the production mandrel assembly with a bolted coupling device 20. This bull plug protects the internal surfaces of the assembly from fouling and sea water corrosion and acts as a secondary seal for the valve 15. A tubing safety joint 16 with a shoulder 24 is att-ached to the top of the valve housing 14 for use in lowering the production mandrel assembly from the drilling barge to the ocean floor and for connection to a riser or lubricator 26, as will be hereinafter set forth. The coupling device 20 attaches at the shouldered portion 22 to the shoulder 24 of the safety joint 16 and may be a manually releasable connector, such as a unibolt coupling.

When it is desirable to install or remove downhole pumping apparatus through the production head 10, the bull plug 18 is removed by uncoupling the coupling device 20 and inserting a conduit such as riser or lubricator 26 which extends to the drilling vessel (not shown). The production head, with the lubricator 26 attached thereto, is shown in FIG. 2. With the lubricator coupled to the production head, a fluid-operated pump 30 may be lowered or retrieved from or to the vessel through the lubricator, and the production head into or from the lower section of the well tubing 28 as shown in FIG. 10. The pump 30, which is preferably a conventional free pump, may be circulated into or out of its downhole operating position, shown in FIG. 10, with power oil in a conventional manner. The pump may also be equipped with fishing tool attachment 38 for recovery with fishing equipment.

I prefer to use an open system wherein power oil is pumped from the surface through the tubing outlet 31 down the tubing 28, where it actuates pump 30 and returns to the surface through casing outlet 32 with production oil from the reservoir. Discharge from the casing annulus outlet 32 is washed in tank 34 and separated from the production oil and returned to power oil tank 36, preparatory to being repumped in pump unit 40 through the production tubing 28 to pump 30. During production operations, valve is closed and all flow is through the tubing and casing outlets 31 and 32. When it is desired to retrieve the downhole pump, the coupling is uncoupled, bull plug 18 removed, and lubricator 26 coupled to the safety joint 16 with coupler 20. Valve 15 is then opened and circulation is reversed at the surface to cause power oil to go down the casing annulus, through the tubing opening 42 and up through the tubing 23 to circulate the free pump out of the hole in a conventional manner. My present system thus permits the operator to circulate the bottom hole pump 30 in or out of the well for inspection or repair.

Although my invention has been described with a certain degree of conciseness, the scope of my invention is not to be limited to the details set forth, but should be given the full breadth of the appended claims.

I claim:

1. An underwater production system for pumping oil and gas from a well drilled in a formation underlying a body of water from a structure over the body of water, through a production head comprising a first tubular member having a side outlet disposed within but fiow isolated from a second tubular member having a side outlet with means in said second tubular member for supporting said first tubular member within said second tubular member, the improvement comprising: a tubular riser extending from said first tubular member to said structure, a valved member connected to said first tubular member for shutting off fluid flow above said first tubular member, a downhole pump positionable through said first tubular member, and means for circulating power oil through the second tubular member side outlet down the annulus between said first and second tubular members and up through said first tubular member and riser to said structure when said valve member is open thereby conveying said pump to said structure.

2. A method for pumping oil and gas from a well drilled in a formation underlying a body of water from a structure on said body of water, through a production head at said formation wherein a first tubular member having a tubing outlet is disposed within but flow isolated from a second tubular member having a casing outlet, comprising the steps of: circulating power oil under pressure through said tubing outlet to a downhole fluid-actuated pump positioned in said tubing, recovering said power oil together with well production through said casing outlet installing a tubular riser between said vessel and said first tubular member, and recovering said pump through said first tubular member and said riser to said structure.

3. A method for recovering a downhole fluid-operated pump through a production head mounted on a formation underlying a body of water from a vessel over said body of water, said production head having a first tubular member having a tubing outlet disposed Within but flow isolated from a second tubular member having a casing outlet, said head having a shutoff valve thereon and a protector cap above said valve, comprising the steps of: replacing said protector cap with a riser extending between said production head and said drilling vessel, opening said shutoff valve, circulating power oil through said casing outlet down the annulus between said first and second tubular members, into said first tubular member below said downhole pump and up said first tubular mem ber and riser to said vessel thereby recovering said pump at said vessel.

4. Apparatus for producing oil and gas from a well drilled in a formation underlying a body of water from a drilling structure comprising: a first tubular member affixed to said formation, a second member supported within but flow isolated from said first tubular member,

a downhole fluid actuated pump positioned in said second tubular member, means for circulating power oil under pressure through said second tubular member, means for recovering said power oil together with well production fiuid through the annulus between said first and second tubular members, and valved tubular riser means insertable between said drilling structure and said second tubular member for recovering said pump through said second tubular member to said drilling structure.

5. A method for producing petroleum from a well drilled in a formation underlying a body of water from a structure over said body of water, through a production head wherein a first tubular member is supported Within but fiow isolated from a second tubular member and wherein said head has a tubing outlet communicating with said first tubular member and a casing outlet communicating With said second tubular member and wherein said first tubular member has a normally closed shutoff valve therein above said tubing outlet, comprising the steps of:

circulating power oil under pressure through said tubing outlet to a downhole fluid-actuated pump positioned in said first tubular member,

recovering said power oil together with said well production through said casing outlet,

connecting a conduit from said structure to said first tubular member above said shutoff valve,

opening said valve, and

retrieving said pump through said first tubular member and said conduit to said structure.

6. A method for producing petroleum from a well drilled in a formation underlying a body of water from a structure over said body of water, through a production head wherein a first tubular member is supported within but flow isolated from a second tubular member and wherein said head has a tubular outlet communicating with said first tubular member and a casing outlet communicating with said second tubular member and wherein first tubular member has a normally closed shutoff valve therein above said tubing outlet and a protector cap above said valve, comprising the steps of:

circulating power oil under pressure through said tubing outlet to a downhole fluid-actuated pump positioned in said first tubular member,

recovering said power oil together with said well production through said casing outlet,

replacing said protector cap with the lower end of a conduit extending to said structure and communicating with said first tubular member above said shut off valve,

opening said shutoff valve, and

retrieving said pump through said first tubular member to said structure.

7. An apparatus for producing petroleum from a well drilled in a formation underlying a body of water from a structure over said body of water, through a production head wherein a first tubular member is supported within but flow isolated from a second tubular member and wherein said head has a tubing outlet communicating with said first tubular member and a casing outlet communicating with said second tubular member, comprising in combination:

a shutoff valve in said first tubular member above said tubing outlet,

a downhole fluid-actuated pump positioned in said first tubular member,

means for circulating power oil under pressure through said tubing outlet to said pump positioned in said first tubular member,

means for recovering power oil together with said well production through said casing outlet,

a closure member for closing off said tubular member above said shutoff valve,

means for coupling said closure to said tubular member above said shutoff valve, said coupling means being connectible to the lower end of a conduit from said vessel when said closure member is uncoupled therefrom.

8. An underwater production system for pumping oil and gas from a Well drilled in a formation underlying a body of Water from a structure over the body of water, through a production head comprising a first tubular member having a side outlet disposed within but flow isolated from a second tubular member having a side outlet with means in said second tubular member for supporting said first tubular member within said second tubular member, the improvement comprising: a downhole pump positionable through said first tubular member, a valved member connected to said first tubular member for shutting otf fluid flow above said first tubular member, a tubular riser extending from said first tubular member to said structure, and means for retrieving said pump to said structure through said first tubular member and said riser when said valved member is open.

References Cited by the Examiner UNITED STATES PATENTS Roberts 166-66 Crites et a1. 16645 Coberly 10346 Chenault 10346 Reistle 16646 Morse et al. 166--46 Geer 16666.5

Meyers 16645 Haeber 166-66 JACOB L. NACKENOFF, Primary Examiner.

5 CHARLES E. OCONNELL, Examiner.

T. A. ZALENSKI, R. E. FAVREAU,

Assistant Examiners. 

8. AN UNDERWATER PRODUCTION SYSTEM FOR PUMPING OIL AND GAS FROM A WELL DRILLED IN A FORMATION UNDERLYING A BODY OF WATER FROM A STRUCTURE OVER THE BODY OF WATER, THROUGH A PRODUCTION HEAD COMPRISING A FIRST TUBULAR MEMBER HAVING A SIDE OUTLET DISPOSED WITHIN BUT FLOW ISOLATED FROM A SECOND TUBULAR MEMBER HAVING A SIDE OUTLET WITH MEANS IN SAID SECOND TUBULAR MEMBER FOR SUPPORTING SAID FIRST TUBULAR MEMBER WITHIN SAID SECOND TUBULAR MEMBER, THE IMPROVEMENT COMPRISING: A DOWNHOLE PUMP POSITIONABLE THROUGH SAID FIRST TUBULAR MEMBER, A VALVED MEMBER CONNECTED TO SAID FIRST TUBULAR MEMBER FOR SHUTTING OFF FLUID FLOW ABOVE SAID FIRST TUBULAR MEMBER, A TUBULAR RISER EXTENDING FROM SAID FIRST TUBULAR MEMBER TO SAID STRUCTURE, AND MEANS FOR RETRIEVING SAID PUMP TO SAID STRUCTURE THROUGH SAID FIRST TUBULAR MEMBER AND SAID RISER WHEN SAID VALVED MEMBER IS OPEN. 